/*
 * @(#)ChunkedInputStream.java   0.3-3 06/05/2001
 *
 *  This file is part of the HTTPClient package
 *  Copyright (C) 1996-2001 Ronald Tschal�r
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free
 *  Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *  MA 02111-1307, USA
 *
 *  For questions, suggestions, bug-reports, enhancement-requests etc.
 *  I may be contacted at:
 *
 *  ronald@innovation.ch
 *
 *  The HTTPClient's home page is located at:
 *
 *  http://www.innovation.ch/java/HTTPClient/ 
 *
 */

package org.everrest.http.client;

import java.io.EOFException;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * This class de-chunks an input stream.
 * 
 * @version 0.3-3 06/05/2001
 * @author Ronald Tschal�r
 */
class ChunkedInputStream extends FilterInputStream
{
   /**
    * @param is the input stream to dechunk
    */
   ChunkedInputStream(InputStream is)
   {
      super(is);
   }

   byte[] one = new byte[1];

   public synchronized int read() throws IOException
   {
      int b = read(one, 0, 1);
      if (b == 1)
         return (one[0] & 0xff);
      else
         return -1;
   }

   private long chunk_len = -1;

   private boolean eof = false;

   public synchronized int read(byte[] buf, int off, int len) throws IOException
   {
      if (eof)
         return -1;

      if (chunk_len == -1) // it's a new chunk
      {
         try
         {
            chunk_len = Codecs.getChunkLength(in);
         }
         catch (ParseException pe)
         {
            throw new IOException(pe.toString());
         }
      }

      if (chunk_len > 0) // it's data
      {
         if (len > chunk_len)
            len = (int)chunk_len;
         int rcvd = in.read(buf, off, len);
         if (rcvd == -1)
            throw new EOFException("Premature EOF encountered");

         chunk_len -= rcvd;
         if (chunk_len == 0) // got the whole chunk
         {
            in.read(); // CR
            in.read(); // LF
            chunk_len = -1;
         }

         return rcvd;
      }
      else
      // the footers (trailers)
      {
         // discard
         Request dummy = new Request(null, null, null, null, null, null, false);
         new Response(dummy, null).readTrailers(in);

         eof = true;
         return -1;
      }
   }

   public synchronized long skip(long num) throws IOException
   {
      byte[] tmp = new byte[(int)num];
      int got = read(tmp, 0, (int)num);

      if (got > 0)
         return (long)got;
      else
         return 0L;
   }

   public synchronized int available() throws IOException
   {
      if (eof)
         return 0;

      if (chunk_len != -1)
         return (int)chunk_len + in.available();
      else
         return in.available();
   }
}
